Mediterranean climate: Encyclopedia II - Mediterranean climate - Precipitation

Mediterranean climate - Precipitation

During summer, regions of Mediterranean climate are dominated by the subtropical high pressure, and are thus equivalent to deserts from the point of view of air mass positions, while during winter the polar front moves equatorward into regions of Mediterranean climate giving weather conditions similar to an oceanic climate. As a result, areas with this climate receive almost all their rain during the winter months, and may go anywhere from 2-5 months during the summer without having any significant precipitation.

As an example, San Francisco in California, USA, has an average of 448 mm (17.6 in.) of rain from November through April each year, but averages only 52 mm (2 in.) of rain for the rest of the year.

Adapted from the Wikipedia article "Precipitation", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki